1. Field of the Invention
The present invention relates to automotive window clearing systems generally, and more specifically to automotive windshield defrosting systems.
2. Description of the Related Art
In motor vehicles operated in cool climates, the need often arises to defrost the windows of the vehicle. The oldest method of defrosting the windows is with a forced-air defroster system, which directs heated air to the windows. The air is typically heated by a heater core through which engine coolant is circulated.
However, in some applications, particularly trucks with diesel engines, it can take a very long time for the engine coolant to warm to the point that the heater core can transfer significant heat to air directed toward the windows. In this case, a system which begins delivering heat immediately will be advantageous.
One such system which begins to deliver heat immediately employs a conductive layer embedded in the windshield. Electric current is applied to the conductive layer, causing it to heat.
Although such a heated windshield system is effective, it is fairly expensive. Additionally, in truck applications, windshields are often chipped or cracked due to stones kicked up against the windshield. Frequent replacement of the windshield of such a heated windshield system can be very costly.
An additional concern in the application of such a heated windshield system is that the conductor embedded in the windshield presents a very substantial load on the vehicle charging system. Without effective control of energy provided to the conductor, other electrical devices on the vehicle can be deprived of sufficient power to operate properly. Further, the battery of the vehicle can become discharged, leading to inability to start the vehicle during a subsequent attempt to start it.
Therefore, a system which provides immediate heat to a windshield without requiring a conductor embedded in the windshield and without over-taxing the vehicle's charging system can provide advantages over the prior art.